South Korean study: BPS, BPF disrupt zebrafish thyroid function

BPA "analogues" BPS and BPF can disrupt thyroid function in aquatic organisms, and may even be more potent in this regard than BPA, according to a study by scientists in South Korea.

The finding will increase concerns about the growing trend of manufacturers substituting BPA in their products for these compounds, which are structurally similar at the molecular level, but are much less well understood in terms of toxicity.

Sangwoo Lee, a postdoctoral researcher at the Korea Institute of Toxicology, led the team, which was affiliated with Seoul National University, the CRI Global Institute of Toxicology and Eulji University.

They tested the substances on zebrafish embryos and larva to investigate effects on thyroid function, an indicator of endocrine disruption.

BPS and BPF both caused significant increases in thyroid hormones levels. Furthermore, BPF caused increases in levels of hormone T4 at exposure levels that were lower than those for BPA.

The overall picture, however, was complex. BPZ caused decreases in levels of T4 and another hormone, T3. Meanwhile, despite causing similar thyroid effects, the impact on gene transcription was subtly different for BPS compared with BPA and BPF, suggesting different modes of action.

"Our findings suggest that BPF and BPS might not be safer alternatives to BPA in terms of thyroid hormone disruption," the scientists conclude in their paper, published in Chemosphere.